Reverb as a plug-in

So I'm starting to understand that reverb helps create depth and a sense of space when you are mixing different channels in a DAW. That being said, would a reverb VST be applied to an acapella for example after its recorded? or is it something i enable while I am recording? Sorry if that sounds like a noob question

i think that's all in post. usually you don't want a bunch of reverb you can't take away when you're mixing stuff...the only time i've really heard of artists intentionally doing that is when Crystal Castles recorded their second album in a large church.

You can do either really. As far as a VST goes. You can record the vocals with the VST on the FX chain in real time. That doesn't mean you're going to be printing it to audio. Some people like to hear reverb on their voice when they're recording, helps them to hear their voice not so raw.